A Study on the Effect of Field Shaping on Dose Distribution of Electron Beams.
- Author:
Wee Saing KANG
1
;
Moon June CHO
Author Information
1. Department of Therapeutic Radiology, College of Medicine, Seoul National University, Korea.
- Publication Type:Original Article
- Keywords:
Electron beam;
Shaped field;
Output factor and Equivalent field
- MeSH:
Alloys;
Polystyrenes
- From:Journal of the Korean Society for Therapeutic Radiology
1986;4(2):165-172
- CountryRepublic of Korea
- Language:English
-
Abstract:
In electron therapy, lead cutout or low-melting alloy block is used for shaping the field. Material for shaping electron field affects the output factor as well as the collimation system. The authors measured the output factors of electron beams for shaped fields from Clinac-18 using ionization chamber of Farmer type on polystyrene phantom. They analyzed the incident energy, collimation system and size of shaped field. For shaped field the variation of output factor for the field (A/P) has appearance of a smooth curve for all energy and all applicator collimator combination. The output factors for open field deviate from the curves for shaped fields. An output factor for a given field can be calculated by equivalent field method such as A/P method, if a combination of applicator and collimator is fixed.
